RECENT ADVANCE IN OIL BURNING. 157 
Through the courtesy of the Navy Department I am able to include in this 
paper the official results of the last two series of these tests in the tables, Plates 64 
and 65, and I have taken the liberty of giving the plotted efficiency results of all four 
series in Plate 63. 
It will be noted that in the highest capacity test of June 10, 1919, there were 
eleven burners in operation, each atomizing 1,032 pounds of Navy Standard Oil 
(25.5 Baumé) per hour, giving a consumption of 1.5 pounds of oil per square foot 
of heating surface per hour. The evaporation of water per pound of oil from and 
at 212° F. was 15.14 pounds, giving an evaporation of water per square foot of 
heating surface per hour of 22.73 pounds from and at 212° with an efficiency of 
76.15 per cent. The air pressure in the closed fire-room was 9.5 inches and the 
rate of combustion per cubic foot of furnace volume reached the very high figure 
of 15.12 pounds of oil per hour. It is believed that this test stands as a world’s 
record for efficiency at high boiler and furnace capacity. 
In the burning of oil there are many things more important than the mere 
cate of combustion as measured in pounds of oil per square foot of heating surface. 
The latter applies rather more to the boiler, and the ultimate capacity is a function 
of efficiency in heat absorption as well as the amount of oil burned. But it is 
interesting to note that tests have been made in England by Babcock & Wilcox, 
Ltd., in which the rate of combustion practically equalled 134 pounds of oil per 
square foot of heating surface per hour. I am indebted to The Babcock and 
Wilcox Company of New York for the following memorandum concerning these 
tests. Under date of September 9, 1920, my friend and former colleague, Capt. 
Walter M. McFarland, writes: 
“The test of a Babcock and Wilcox boiler was made at Renfrew in the early 
part of 1917. This boiler was composed almost entirely of small tubes and was 
entirely experimental, as a first step in a series of studies. 
“Six tests were made, in which the oil was burned at a rate of 1.2 pounds 
per square foot of heating surface per hour, or higher; one test was at the rate of 
1.53 pounds with an air pressure of 2 inches, and the last was at the rate of 
1.74 pounds with an air pressure of 2.08 inches. In the former case the baffling 
was of checkerwork on the top of the tubes, while in the latter there was no baffling 
at all.”” The oil burned per cubic foot of furnace volume at the highest rate was 
11.64 pounds per hour. 
In a paper before the Institution of Naval Architects presented by Mr. 
Harold Yarrow some years ago, reprinted in the Journal of the American Society 
of Naval Engineers for May, 1912, a test on a Yarrow boiler was reported in which 
the figures 1.94 were given as the rate of combustion in pounds of oil per square 
foot of heating surface per hour. It is to be noted, however, that in this test a 
damper in the uptake over one bank of tubes was closed and that the above high 
rate of combustion was reported on the assumption that only half of the 
heating surface was making steam. ‘This assumption is, of course, unjustified, 
and it appears that the highest rate obtained in the Yarrow test was 1.24 per 
square foot of heating surface. 
